Fix bug in bos/eos handling.

CRE-SEARCH? (defined in scsh/rx/re-low.scm) calls REGEXP-MATCH with
4th and 5th arguments indicating whether this corresponds to begin/end
of line. For matching a string, these must be #t. The reason it was
working previously (with both parameters set to #f) was a bug in
regexp1.c:116 (fixed now by placing the appropriate parenthesis),
caused by | having higher precedence than ?: in C (as a result, the
flags passed to the C regexp engine were not correctly computed).

scsh/rx/re-low.scm

@@ -81,7 +81,7 @@
 	  (let ((ret (regexp-match (cre:regexp cre) str #t #f #f start)))
 	    (if (not ret)
 		#f
-		(make-regexp-match str 
+		(make-regexp-match str
 				   (translate-submatches ret
 							 (cre:tvec cre)
 							 match-vec))))))))
@@ -114,4 +114,4 @@
 	  (if (not (cre:regexp/nm cre))
 	      (set-cre:regexp/nm cre (make-regexp re-str
 						  (regexp-option extended))))
-	  (regexp-match (cre:regexp/nm cre) str #f #f #f start)))))
+	  (regexp-match (cre:regexp/nm cre) str #f #t #t start)))))